#include <stdio.h>

int flag = 0;

int sum(int s, int e){
  int sum = 0;
  int i = s;
  for(; i <= e; i++) sum += i;
  return sum * flag;
}

int div(int x, int y)
{
  if(y == 0) return -1;
  int z = x / y;
  return z;
}

int main()
{
  printf("process is running ");
  int  start = 1;
  int end = 100;
  int result = sum(start, end);
  printf("process is done, result: %d\n",result);
  
  int a =  div(10, 0);
  printf("process is done, result: %d\n",a);

}

